Display system

ABSTRACT

The present invention relates to a display system having a large number of display panels. Each display panel comprises a large number of light-emitting elements. The display system further includes a system control for actuating the display panels and a data bus which connects the system control to each of the display panels.

The present invention relates to a display system having a large numberof light-emitting elements. The display system is adapted to provide apredetermined representation, in particular on a screen, by the lightemission of the light-emitting elements being suitably controlled.

STATE OF THE ART

The present invention is based on the display system disclosed in patentapplication EP 1 293 955 A2. EP 1 293 955 A2 discloses a displayarrangement comprising a holding element and a large number oflight-emitting elements fixed to the holding element. The arrangement isadapted to represent desired representations in a screen-like fashion,by the light emission of the light-emitting elements being suitablycontrolled. The display arrangement includes a display panel oflight-emitting elements. The display panel has a holding frame and alarge number of bars with light-emitting elements which are arrangedparallel and at a uniform spacing relative to each other. The bars aresecured to the holding frame. Each bar is enclosed by a cylindricaltranslucent tube.

The display arrangement of EP 1 293 955 A2 additionally includes a lightemission control means including a computer which is adapted to controlthe light emission of the large number of bars with light-emittingelements in the display panel. The bar of the display arrangement in thestate of the art includes in particular a cylindrical translucent tubeand a display module arranged in the translucent tube. The displaymodule includes an elongate structural assembly and light-emittingelements in the form of a large number of pixels arranged along a linein the longitudinal direction of the elongate circuitry structuralassembly. Each pixel includes LEDs of the three primary colors red (R),blue (B) and green (G) and a circuit for control of the light emission,which is connected to the pixels.

In particular it is provided that a large number of light-emittingdisplay panels is connected to the arrangement to be provided. Thelight-emitting display panels are arranged in accordance with apredetermined pattern in the vertical and horizontal directions. Inaddition they are fixed flexibly to each other. The pixels in thedisplay modules are arranged in the form of a matrix in thelight-emitting display panels. The control circuit actuates theindividual pixels in the matrix and controls the light emission thereof,thereby producing a color image.

A control system for actuation of the display panels is provided inconventional fashion. The control system usually includes a controlcomprising a master computer and a plurality of slave computers. Thecontrol system generates bitmap image data which are stored in thecontrol. The master computer generates the bitmap image data and outputsthem to the slave computers. Each slave computer is connected to one ofthe display panels by way of a signal cable. An internal control portionof each display panel receives the image data by way of the connectedsignal cables to actuate the individual light-emitting elementsaccordingly.

A disadvantage with the previously known actuating system is that, inthe construction of the display panels, each of those display panels hasto be connected to a slave computer of the control by way of a specialdata cable. With a large number of display panels, a correspondingnumber of cables has to be laid. Conventionally, what are referred to asmulticore cables are connected to the actuating system. A multicorecable conventionally includes up to 72 individual data lines. Theconnection of each individual data line to the corresponding displaypanel is a laborious and time-consuming operation.

Therefore the object of the present invention is to provide a displaysystem which can be easily and quickly constructed.

That object is attained by the display system of claim 1. The displaysystem according to the invention has a large number of display panelswhich each have a large number of light-emitting elements. The displaysystem further includes a system control for actuation of the displaypanels. A single data bus connects the system control to each of thedisplay panels.

A data bus is a subsystem of a computer architecture, which exchangesdata between various bus subscribers. The system control and the displaypanels are each bus subscribers. By definition there is a data busprecisely when the flow of data is from a bus subscriber to all otherbus subscribers. If a bus subscriber outputs data on to the data bus,those data go to all bus subscribers. Unlike the situation with aconventional connection, a bus can communicate a plurality ofapparatuses with each other by way of the same set of lines. A data buscan be physically set up by all bus subscribers being connected to anindividual cable by way of what are referred to as T-connectors. Thatsituation involves what is referred to as a bus topology. The bussubscribers however can also be connected together as links in a chain.The flow of data goes then from a chain link (bus subscriber) to thenext bus subscriber. In that case also the data go to each bussubscriber, and for that reason the situation also involves a data bus.

The advantage of the data bus lies in the simple cabling of the bussubscribers. The cabling requirement of the data bus is less than in thecase of conventional cabling in which all display systems are connectedin a star configuration to the system control. In addition it is easierto connect further bus subscribers to the display system. The displaysystem can be easily expanded by further display modules. In that casethe display modules are only connected to the data bus.

Preferably twisted pair cables, in particular Cat 5 cables are used forcabling of the individual bus subscribers. In computer technology theterm twisted pair cable is used to identify types of cables in which thetwo wires of a pair of wires are twisted together (also stranded orbraided). Data transfer is less susceptible to trouble due to thetwisting of the respective outgoing line with the return line of acurrent loop (the pair of wires).

The Cat 5 cable is a particular twisted pair cable used for signaltransmission with high data transfer rates. The specific standardidentification is EIA/TIA-568. Because of the high signal frequenciesoperation must be particularly carefully implemented in the laying andassembly procedures, particularly at the connecting locations of thewires, and the manufacturing specifications have to be observed.Category 5 cables are frequently used in the structured cabling ofcomputer networks such as for example Ethernet. The Cat 5e cable is anenhanced version of Cat 5 for use in 1000BASE-T-networks or forlong-distance 100BASE-T-network connections (350 m, compared to 100 mfor Cat 5). It must comply with the specification of EIA/TIA-568A-5which however in the meantime has been superseded by the specificationEIA/TIA-568B.

Preferably the system control is used as the bus master and the displaypanels each function as bus slaves of the data bus. The componentsconnected to a bus are also referred to as nodes or bus subscribers.Nodes which may independently access the bus are referred to as activenodes or masters, otherwise they are referred to as passive nodes orslaves. A plurality of bus subscribers cannot simultaneously access thebus because for example a plurality of data packets which aretransmitted at the same time interfere with each other and cause mutualdisturbance. A bus which allows a plurality of master nodes is referredto as a multimaster bus. With multimaster buses, bus access has to becontrolled by a specific component which is referred to as the busarbiter. That node which initiates an access to the bus is referred toas the initiator while the aim of such (reading or writing) access isreferred to as the target. Such a structure is considerably morecomplicated and expensive as additional components like the arbiter arerequired. As there is generally no need for the display panels toautomatically transmit items of information to the system control, thesystem control can be set up as the sole bus master. The display systemis thus less expensive and simpler to operate.

Preferably the system control is adapted to transmit data serially inthe form of data packets by way of the data bus to a predetermineddisplay panel. In serial data transmission data are transmitted insuccession by way of a given medium, here the bus line. So that the datago to the predetermined display panel, each data packet contains areceiver address for the predetermined display panel. Precisely oneaddress is allocated to each display panel in the bus system. Thedisplay panels are then adapted to recognise on the basis of thereceiver address whether the data packet is addressed to the displaypanel in question. The system control passes the data packet to the databus. The data packet automatically goes by way of the data bus to eachconnected display panel. The display panels decide on the basis of thereceiver address whether they process or reject the data packet.

The display system according to the invention preferably includes aplurality of system controls which can each be connected by way of adedicated data bus to a predetermined number of display panels. Thefinite data transmission capacity of the data bus means that the numberof connected display panels is limited so that moving images can berepresented in a high state of resolution on the display panels.Preferably display panels which are made up from 256 RGB pixels areused.

The display system is for example of such a design configuration that amaximum of 12 display panels can be connected to a system control by wayof a data bus. Further display panels can be managed by the displaysystem only when further system controls are provided. Preferably thearrangement has a synchronisation device for the synchronisation of thesystem controls. The system controls have to be synchronised if the timesuccession of images or video sequences on the display panels is to befixed. The system controls each have so-to-speak a respective clock.Each of the clocks is synchronised when it displays the same time ateach moment in time. Synchronisation can be effected for example by thesystem controls receiving the same clock signal.

The system control preferably includes a representation of a positioningand orientation of the display panels in a co-ordinate system. Thatrepresentation is also referred to as a virtual screen. The large numberof display panels connected to the system control generally forms acontinuous unitary screen surface for a viewer when viewed from adistance. The endeavour is therefore to display overall a singleinterconnected continuous image on the display panels. For that purposethe system control receives all items of information relating to theposition and orientation of the display panels. Those items ofinformation are preferably put into a two-dimensional co-ordinatesystem.

For any image represented in the co-ordinate system, corresponding itemsof image information in respect of each display panel can be calculatedon the basis of the respective positioning and orientation. All items ofimage information which are in the region of a display panel in theco-ordinate system have to be represented by the corresponding pixels ofthe display panel. The system control associates the individual pixelswith the different display panels. In particular the system controldetermines which light-emitting elements of the display panel have toreproduce the items of image information.

Each display panel preferably includes a dedicated internal signalprocessing device. In that way each display panel can be connected bymeans of conventional twisted pair cables in series to another displaypanel with any desired line length.

Each display panel preferably has light-emitting elements in the form ofLEDs (light-emitting diodes) and drivers for driving the LEDs. Thedrivers and the LEDs are preferably arranged on a printed circuit boardand disposed with the board in a transparent tube. The display panel hasa plurality of tubes arranged in a row with each other, in each of whichis respectively disposed a board with the driver and the LEDs. A digitalsignal is passed to each driver. As signal processing is effected by thedriver the display tubes, in a fixed installation, can be disposed atany distance from the frame of the display panel. The display tubes areusually actuated jointly from a frame in which the internal signalprocessing device is disposed.

The heat generated by the LED drivers is preferably dissipated by aspecial ventilation device. The ventilation device produces an air flowthrough the tube, which passes the heat generated by the electronicdrivers to the ambient air. The tube is open at both ends. A ventilatoror fan produces the air flow at an open end of the tube. In that casethe heated air is transported away within the tube and replaced by coolambient air.

Preferably the display system according to the invention includesconnecting means which are adapted to releasably secure the displaypanels to each other and to connect the display panels in series witheach other. The connecting means are therefore on the one hand plugconnectors which provide for data to be passed through the data bus. Inaddition the connecting means provides for mechanically securing thedisplay panels to each other. Thus a larger display panel can be easilybuilt up from a plurality of display panels, by the display panels beingfixed to each other by means of the connecting means. Furthermore,standardised connecting means permit a modular structure for the displaysystem so that an existing group of display panels can be easilyenlarged in a simple fashion by a further display panel.

The invention provides a display system which:

-   -   is transparent and can thus be integrated into the background,    -   is of a modular structure but nonetheless requires little        visible image area for the frame,    -   is extremely light so that it can be assembled by only one        engineer but is sufficiently stable to be transportable and        withstands being repeatedly assembled and dismantled,    -   is quick and easy to assemble, by virtue of a self-locking        plug-in system,    -   is quick and easy to assemble by virtue of using only one        RJ45-cable Cat 5 for data transmission,    -   can be quickly assembled to afford systems of any size,    -   is flexible in construction in order to bridge over even        relatively large spacings between the modules,    -   can be used in mobile fashion during operation,    -   can be used indoors and outdoors temporarily and also        stationarily, and    -   has a high luminosity in respect of the LEDs with at the same        time a large emission angle so that an image which remains of        the same brightness appears in all viewing directions.

Preferred embodiments by way of example of the present invention aredescribed hereinafter with reference to the accompanying Figures inwhich:

FIG. 1 shows a diagrammatic view of an embodiment of the display systemaccording to the invention,

FIG. 2 a shows an embodiment of a virtual screen with virtual image andvirtual display panels,

FIG. 2 b shows the virtual screen of FIG. 2 a, in which the virtualimage is shown only in the region of the display panels,

FIG. 3 shows a diagrammatic view of an embodiment of the display systemaccording to the invention,

FIG. 4 shows a perspective view of the display panel of FIG. 3,

FIG. 5 shows a diagrammatic view of a block circuit diagram of theembodiment of the display system according to the invention,

FIG. 6 a shows an embodiment of an arrangement of the display panelsaccording to the invention,

FIG. 6 b shows two connecting shafts for connecting two display panelsaccording to the invention,

FIG. 6 c shows a perspective view of an embodiment of an arrangement ofthe display panels according to the invention,

FIG. 7 a shows a socket of a first embodiment of a connecting meansaccording to the invention,

FIG. 7 b shows a plug of a first embodiment of the connecting meansaccording to the invention,

FIG. 7 c shows the socket of FIG. 7 a and the plug of 7 b in theassembled condition,

FIG. 8 shows a diagrammatic view of a second embodiment of theconnecting means according to the invention,

FIG. 9 shows an exploded view of the connecting means according to theinvention,

FIG. 10 a shows an upper portion of the display panel according to theinvention,

FIG. 10 b shows a lower portion of the display panel according to theinvention,

FIG. 11 a shows a cross-sectional view of the connecting means accordingto the invention in the open condition,

FIG. 11 b shows a cross-sectional view of the connecting means accordingto the invention in the closed condition, and

FIG. 12 shows an exploded view of a connecting bar for connecting thedisplay panels according to the invention.

FIG. 1 diagrammatically shows an embodiment of the display systemaccording to the invention. The display system includes a personalcomputer 10 which serves to control the display panels. The personalcomputer 10 has a graphics card. The computations for generating theimage data for the display system are effected by means of the graphicscard. The graphics card has a chipset which is specialised forperforming graphics computations and which on the one hand acceleratesthe computations and on the other hand relieves the load on theprocessor. Connected to an interface card 12 is a Cat 5 cable 14 whichfunctions as a bus line. A display panel in FIG. 1 includes an upperframe 16 and a lower frame. The bus line 14 connects the upper frame 16of the display panel to the interface card 12 of the personal computer10.

The upper frame portion 16 of the display panel comprises an aluminumhousing in which all of the control electronics are disposed. Acommunication unit 22 and a CPU 24, that is to say a central processingunit, are constituent parts of the control electronics of the displaypanel. The display panel accordingly has an independent computing unitwhich for example could at least partially take over computation of thecontrol signals for the graphic representation of the display panel,from the graphics card 12. The communication unit 22 and the CPU howeverare predominantly provided to permit data exchange between the systemcontrol 12 and the other (not shown) display panels by way of the databus, wherein the communication unit 22 receives the data packets passingby way of the data bus and puts them into intermediate storage. Afurther bus line 28 is provided, which connects the illustrated displaypanel to the next display panel which is not illustrated here.

The CPU, on the basis of the address fields of the received datapackets, ascertains whether they are intended for the illustrateddisplay panel. Each display panel and the system control have a uniqueaddress in the data bus. The bus data are transmitted serially, that isto say in succession, by way of the bus lines. Each data packet includesan address field specifying the address of the display panel to whichthe data packet is to pass. If the CPU 24 recognises that the address inthe address field is in conformity with the address of its own displaypanel the received data packet is subjected to further processing.Otherwise the data packet is forwarded to the next display panel by wayof the bus line 28.

The display system is of a modular structure, wherein each display panelcomprises for example 256 RGB pixels which are arranged in atwo-dimensional raster of 60 mm. The display panels represent themodules of the display system. By virtue of the two-dimensional raster,intermediate spaces are formed, which are used for transparent imagegeneration on stages of theaters or in architecture.

Sixteen transparent polycarbonate tubes are fixedly connected atspacings of 60 mm to the frame of the display panel. One of those tubes18 is diagrammatically shown in FIG. 1. Disposed in each of those tubesis a long narrow circuit board on which a total of sixteen light dotsare distributed at a spacing of 60 mm. Each light dot consists ofprecisely one red, one green and one blue light-emitting diode (LED). InFIG. 1 the red-lighting LEDs are identified by reference 20 a, thegreen-lighting LEDs are identified by reference 20 b and theblue-lighting LEDs are identified by 20 c. Also disposed on that circuitboard are the driver ICs for the LEDs. The abbreviation IC stands forintegrated circuit. Consequently the drivers are also embodied in theform of a circuit arrangement on the board. The CPU processes the imagedata received by way of the bus line 16 and outputs them in suitableform to the corresponding driver ICs.

At least one respective LED in the colors red, green and blue is used asthe light-emitting means. Manufacturers are for example Digital Light,Nichia or Everlight. The LEDs light up in the primary colors which byvirtue of their specific selection permit any color mixing in the colorspectrum. The same effect can be achieved by the use of RGB-LEDs. Theseare LEDs with three different crystals in a housing. It is also possibleto use SMD-LEDs. When selecting the LEDs, attention is to be paid to alarge radiation angle of at least 70° with at the same time a high levelof light intensity. In addition LEDs of the highest color and intensityselection step are used to avoid color and brightness differences. Colorand brightness differences are visible precisely in relation toparticularly large systems composed of many individual modules.

Regulation of the brightness of an LED can be effected by regulating thecurrent through the LED or by pulse width modulation (PWM).

In brightness regulation by virtue of varying the current through theLED, the color shade of the LED changes. In addition the brightnesscannot be continuously reduced down to zero as each LED needs a minimumcurrent for lighting up.

Therefore pulse width modulation (PWM) is preferred for regulating thebrightness of the LEDs. That means that the LED is always operated witha 100% brightness. Regulation is effected by periodically switching theLED on and off. The shorter period of time for which the LED is switchedon during a unit of time, the correspondingly lower is the level ofbrightness. In order to avoid visible flickering of the LED in thecamera image, the pulse is subdivided and individual or partial pulsesare distributed uniformly over the duration of the original time windowof the 100% pulse. In that case the duration of the individual pulses iscorrespondingly shortened so that the area of the individual pulses(energy) remains of the same magnitude, that is to say equal to the 100%output pulse.

FIG. 2 a shows an embodiment of a virtual screen 30 with a virtual imageand virtual display panels 32 and 34. The virtual screen 30 could berepresented for example on a monitor 10 a connected to the personalcomputer 10. Shown in the virtual screen 30 is an image which isintended to be displayed by the display panels 32 and 34 connected tothe personal computer 10. A control software is installed on thepersonal computer 10. In what is referred to as the frame setup (virtualscreen), a user can cause the image to be represented on the displaypanels 32, 34, to be displayed on the screen 10 a of the PC 10.

The screen 30 reproduces true to scale the position and orientation ofthe actual display panels, wherein the representation of the virtualdisplay panel 34 shows that the display panel corresponding to thevirtual display panel 34 is rotated. The image represented in front ofor with the virtual display panels 32, in FIG. 2 a, graphicallyrepresents the text ‘G-LEC #’. FIG. 2 b again shows the virtual screen.In this case however, only those regions of the text which are on one ofthe virtual display panels 32 and 34 are shown. The virtual screen 30 inFIG. 2 b therefore reproduces true to scale, how the text ‘G-LEC’ wouldbe represented by the display panels which are actually connected.

The display system described herein serves for the representation ofanimations, images or videos in real time. For that purpose any NTSCsignal or DMX512/1990 can be used for that purpose. Any data file formatcan be processed for the representation of images. Played live videos,images and animations can be represented in combination by means of2-layer technology in 24 bit full color RGB.

FIG. 3 shows a diagrammatic view of an embodiment of a display panelaccording to the invention. The display panel is shown on the one handin a front view 38, a side view 40 and a plan view or a view from below46. The display panel in FIG. 3 includes tubes which are made frompolycarbonate. The lower open end of those polycarbonate tubes is fixedin position with an aluminum rail. Fans or ventilators 48 installed inthe underside of the display panel cause air to flow through the tubes38, whereby the LED drivers and the electronics of the display panel arecooled.

Fans 48 are supplied with power by way of electrical conductors 50. Twobars form the lateral frame 42 of the display panel and connect anupwardly disposed housing to a downwardly disposed aluminum rail. Thatforms a stable display module which is independent in itself. Disposedat the lower end of each connecting bar is a quick-action fastener 44.The counterpart portion 45 matching the quick-action fastener 44 isdisposed at the upper end of the lateral frame 42. FIG. 4 shows aperspective view of the display panel 52.

FIG. 5 shows a diagrammatic view of a block circuit diagram of theembodiment of the display system according to the invention. The displaysystem includes a plurality of system controls 54 a, 54 b, 54 c and 54 din the form of personal computers. Each of the system controls 54 a, 54b, 54 c and 54 d is connected by way of corresponding data lines 58 a,58 b, 58 c and 58 d and mains units 60 a, 60 b, 60 c and 60 d for powersupply to precisely 12 display panels. The display panels 62 a-1 through62 a-12 are associated with the system control 54 a; the display panels62 b-1 through 62 b-12 are associated with the system control 54 b; thedisplay panels 62 c-1 through 62 c-12 are associated with the systemcontrol 54 c; the display panels 62 d-1 through 62 d-12 are associatedwith the system control 54 d. The individual system controls 54 athrough 54 d are synchronised with each other by way of a line 56.Twelve respective display panels are actuated with a system control.

Data transmission between PC and display panel is effected with a singleRJ45-cable Cat 5. All further display panels are also connected togetherwith a RJ45 cable. Any number of displays are connected together toafford a large system, in which case a dedicated system control isrequired for each twelve modules. All PCs are synchronised with a syncbox in order to avoid different signal transit times. The sync boxoutputs a clock-controlled signal by way of the line 56 to each of thesystem controls 54 a, 54 b, 54 c and 54 d. The system controls have tobe synchronised with each other so that actuation of the differentdisplay panels can be correlated with each other in respect of time.

FIG. 6 a shows an embodiment of an arrangement of the display panelsaccording to the invention. To produce larger display areas, theindividual display panels 68 are pluggingly connected to each other.Reference 70 identifies two openings in the illustrated display panelarrangement. The individual display panels, except for the openings 70,form a rectangular display area. FIG. 6 c shows the display panelarrangement, as to how it could be fixed to a wall. A support structure64 is mounted in each of the openings 70. In order to be able to suspendthe display system, respective eye nuts 69 are fitted on to theuppermost display panels.

FIG. 6 b shows two connecting bars 66 for the connection of two displaypanels according to the invention. In a horizontal mounting arrangementor when a turned structure is involved, an eye nut can also be fitted onto the quick-action coupling of the lower end of the connecting bar. Inorder to produce the openings 70 upon construction, the connecting bars66 can also be fitted individually. For horizontally connectingindividual display panels 68, thin plates can be inserted between aquick-action coupling and a counterpart portion. Each display panel isof an identical structure and is operational on its own. Display areasof any kind can be constructed in that way.

FIG. 7 a shows a socket 92. The connecting means according to theinvention is a plug connection, wherein the constituent part shown inFIG. 7 a is provided to receive a plug pin 90. The socket 92 has a plugreceiving means 88. The plug 94 shown in FIG. 7 b has a plug pin 90which is provided for being inserted into the plug receiving means 88,thereby forming a plug connection between the plug 94 and the plugsocket 92. The plug 94 further includes a hexagonal external portion 98which can be rotated by means of a suitable wrench. The socket has aseries of features which serve to arrest the inserted plug pin 90: inparticular the socket 92 includes a holding ring and an arresting ball82. The pin 90 in turn has an annular projection 86.

FIG. 7 c shows the socket and the plug in the assembled condition. Thepin 90 is fitted into the plug receiving means and the arresting ball 82is disposed behind the projection 86. In that way the arresting ballprevents the pin 90 from being able to come out of the plug receivingmeans 88 again of its own accord. A sleeve 76 is disposed above thearresting ball and provides that the arresting ball 82 is pressed on tothe pin 90. The sleeve is mounted movably in the longitudinal directionalong the socket 92. A spring 74 provides that the sleeve 76 is over thearresting ball. In addition the sleeve is held in its position by aholding ring 84.

To release the plug connection the sleeve 76 is pushed against thespring force of the spring 74 rearwardly away from the plug receivingmeans until the sleeve is held in a pushed-back position as shown inFIG. 7 a, by an arresting ball 72. The arresting ball 82 can now bemoved in a radial direction away from the plug receiving means. As aresult, the arresting action in respect of the plug pin 90 is releasedfor the arresting ball no longer engages behind the annular projection86. Within the receiving means 88 there is a slider 80 which is biasedby a further spring 74. By means of the spring force, the slider 80pushes the plug pin 90 out of the receiving means.

FIG. 8 shows a diagrammatic view of a further embodiment of theconnecting means according to the invention. This again involves a plugconnection. The plug 102 has a plug pin with an annular projection. Asocket 104 has a plug receiving means 108. Arranged within the plugreceiving means are securing balls 110 which are provided for arrestingthe plug pin 106 in the plug receiving means. The socket 104additionally includes a sleeve 11 which is movable in the longitudinaldirection and which can be arrested by means of a securing ball 114. Atthe end opposite to the plug receiving means, the socket 104 has an eyenut. The plug 102 also has an annular socket 118 which is on the sideopposite to the plug pin 106.

FIG. 9 shows an exploded view of the connecting means of FIG. 8. Theplug includes a screwthreaded bar 142, an external hexagonal portion 140and a screwthreaded pin 145 with a radial projection. The screwthreadedpin 145 has a tip 146 which is substantially cylindrical and is 8 mm indiameter. The plug pin 145 also has a shoulder 144, the cross-section ofwhich is 12 mm in diameter. The hexagonal portion 140 is about 17 mm indiameter.

The socket of the plug connection has an unlocking sleeve 134 of adiameter of 24 mm in cross-section. The unlocking sleeve 134 has asecuring groove 132. The socket further has a securing ball 136 intendedto engage into the securing groove so that the securing sleeve isarrested on the socket. The socket further has a locking bolt member ora slider 138 disposed within a plug receiving means 139. The lockingbolt member is biased by a spring 130 when the plug pin is disposed inthe receiving means.

The assembly also has two arresting balls 126 which hold the plug pin145 fixed in position in the receiving means 139, by engaging behind theannular projection on the plug pin 145. The securing sleeve 134 isfitted over the plug receiving means 139 in the closed condition. Anexternal coil spring 124 is biased and urges the sleeve 134 against asecuring ring 128. The socket has an external hexagonal portion 122 sothat it can be turned with a suitable wrench. It is fixed by means of ascrewthreaded bar to the display panels.

FIG. 10 a shows an upper portion of the display panel according to theinvention. The display panel includes an electronics housing 150 inwhich a communication unit and a central processing unit are disposed.They are connected to further display panels by way of a bus line. Forthat purpose a plug connection 148 is provided in the upper region ofthe display panel. In particular the Figure shows the plug pin 148 whichis provided to be introduced into a corresponding receiving means.

The plug connection provides not only for mechanically holding thedisplay panels together. The plug pin therefore also serves to providean electrical connection. Also shown is a connecting bar 152 which hasan external surface in the form of a hexagon. The connecting bar 152forms the lateral end of the display panel. Display tubes 154 arearranged parallel to the connecting bar. Disposed within the displaytubes are the LEDs in the three primary colors red, green and blue,which are actuated by the CPU within the electronics housing.

FIG. 10 b shows a lower portion of the display panel according to theinvention. Once again the connecting bar 152 of FIG. 10 a and anadjoining display panel 154 are illustrated here. In contrast to FIG. 10a no electronics housing 150 is disposed in the lower region of thedisplay panel. The display tubes are held fast in mutually parallelrelationship by a simple rail. In addition, there is no plug pin in thelower region of the connecting bar 152 but the lower frame 156reinforces the fixing of the connecting bar which at the lower end hasthe counterpart portion in relation to the plug pin—the socket 158.

FIG. 11 a shows a cross-sectional view of the connecting means accordingto the invention in the open condition. A plug pin 166 and an unlockingsocket 160 are each shown in cross-section. The Figure also shows foursecuring balls 162 within the plug receiving means 164 of the socket160. FIG. 11 b shows a cross-sectional view of the connecting means ofFIG. 10 a in the closed condition. The illustrated cross-section of theplug pin is narrowed, in contrast to the cross-section shown in FIG. 11a. For, in FIG. 11 a, the annular radial projection of the plug pinforms the region of the illustrated cross-section. By virtue of thenarrowed cross-section in FIG. 10 b the securing balls 162 are urgedthrough radial holes in the plug receiving means 164 and engage behindthe securing ring of the plug pin. The pin is thus arrested within thereceiving means.

FIG. 12 shows an exploded view of a connecting bar for connecting thedisplay panels according to the invention. The connecting bar centrallyhas an internal bar 176 which is 957 mm long and the externalcross-section of which is the same as that of a hexagon. The internalbar 176 is screwed by means of a screwthreaded bar to a socket 170 of aplug connection according to the invention. For that purpose femalescrewthreads 174 are provided within the internal bar 176 and the socket170 respectively. In just the same way a plug 168 of a connecting meansaccording to the invention is fixed to the opposite end of the internalbar 176. A screwthreaded pin 178 is screwed into female screwthreadsprovided in the internal bar 176 and in the plug 168.

LIST OF REFERENCES

-   10 personal computer-   12 graphics card-   14 data bus (Cat 5 cable)-   16 upper frame of the display panel-   18 LED tube 1-   20 a red LEDs-   20 b green LEDs-   20 c blue LEDs-   22 communication unit of the display panel 16-   24 CPU of the display panel 16-   26 connections for LED tubes 2 through 16-   28 bus line to the next display panel-   30 virtual screen-   32 display panels in the virtual screen 30-   34 display panel (turned through 45°) in the virtual screen 30-   36 display panel-   38 LED tube of the display panel 36-   40 side view of the display panel 36-   42 lateral frame of the display panel 36-   44 quick-action fastener-   45 counterpart portion of the quick-action fastener 44-   46 top view of the display panel 36-   48 fans of the display panel 36-   50 conductors of the display panel 36-   52 perspective view of a display panel-   54 a personal computer-   54 b personal computer-   54 c personal computer-   54 d personal computer-   56 synchronisation of the personal computers 54 a, 54 b, 54 c and 54    d-   58 a data line-   58 b data line-   58 c data line-   58 d data line-   60 a mains unit-   60 b mains unit-   60 c mains unit-   60 d mains unit-   62 a bus line and 48V power line-   62 b bus line and 48V power line-   62 c bus line and 48V power line-   62 d bus line and 48V power line-   62 a-1 through 62 a-12 display panels associated with PC 54 a-   62 b-1 through 62 b-12 display panels associated with PC 54 b-   62 c-1 through 62 c-12 display panels associated with PC 54 c-   62 d-1 through 62 d-12 display panels associated with PC 54 d-   64 support structure-   66 connecting bars-   68 arrangement of display panels-   69 eye nuts-   70 opening in the display panel arrangement 68-   72 ball-   74 spring-   76 sleeve-   78 sleeve spring-   80 cuff-   82 ball-   84 holding ring-   86 annular projection-   88 plug receiving means-   90 plug pin-   92 socket-   94 plug-   96 plug connection-   98 external hexagonal portion-   100 external hexagonal portion-   102 plug-   104 socket-   106 plug pin-   108 plug receiving means-   110 securing ball-   112 sleeve-   114 securing ball-   116 hexagonal portion-   118 eye nut-   120 screwthreaded bar-   122 hexagonal portion-   124 external spiral spring-   126 securing ball-   128 securing ring-   130 internal spiral spring-   132 securing groove-   134 unlocking sleeve-   136 securing ball for socket-   138 locking bolt member-   140 hexagonal portion-   142 screwthreaded bar-   144 shoulder on the plug pin-   146 tip of the plug pin-   148 plug of the quick-action fastener-   150 electronics housing-   152 hexagonal connecting bar-   154 display tubes-   156 lower frame of the display panel-   158 socket of the quick-action fastener-   160 unlocking sleeve-   162 securing ball-   164 plug receiving means-   166 plug pin-   168 plug of the quick-action fastener-   170 socket of the quick-action fastener-   172 screwthreaded bar-   174 female screwthread-   176 hexagonal connecting bar-   178 screwthreaded bar-   180 female screwthread

1-10. (canceled)
 11. A display system comprising a large number ofdisplay panels (32, 34, 36; 62 a-1-62 d-12), each having a large numberof light-emitting diodes (38), and a large number of self-locking plugconnectors for releasably fixing the display panels to each other.
 12. Adisplay system as set forth in claim 11 wherein the plug connector has aplug (94) and a socket (92) for receiving the plug (94), wherein thesocket has arresting means for arresting the plug (94).
 13. A displaysystem as set forth in claim 12 wherein the arresting means have aholding ring and an arresting ball (82), wherein the plug (94) has a pinwith an annular projection (86) which when the plug is inserted into thesocket co-operates in positively locking relationship with the arrestingball in such a way that a self-locking plug connection is produced. 14.A display system as set forth in claim 13 wherein the socket has asleeve (76) which is movable in the longitudinal direction of the socketand which is arranged in the region of the arresting ball (82) in such away that the sleeve (76) urges the arresting ball behind the annularprojection (86) when the plug is inserted into the socket, wherein thesleeve (76) is movable in the longitudinal direction of the socket forreleasing the plug connection.
 15. A display system as set forth inclaim 14 wherein the socket has a spring for biasing the sleeve in anarresting position.
 16. A display system as set forth in claim 14 orclaim 15 wherein the socket has a securing ball for arresting thesleeve, wherein the securing ball engages into a groove in the sleeveupon opening and the sleeve is rotated upon arresting in such a way thatthe securing ball cannot engage into the groove.
 17. A display systemcomprising a plurality of display panels (32, 34, 36; 62 a-1-62 d-12),each having a plurality of light-emitting diodes (38), and a systemcontrol unit (10, 22) for determining a positioning and orientation ofat least one of the display panels (32, 34, 36; 62 a-1-62 d-12) in aco-ordinate system and for computing items of image information for atleast those display panels whose position and orientation have beendetermined for a virtual image which is represented in the co-ordinatesystem.
 18. A display system as set forth in claim 17 wherein the systemcontrol unit is adapted to select display panels whose position andorientation in the co-ordinate system is to be determined.